This is one of those "associations" studies.  It is not science,
because there aren't the proper controls.  We don't know if the omega 9
derived PUFA, Mead acid, would have been just as useful, if not better.
It is clear that the omega 3s can block some of the undeniably
dangerous effects of the omega 6s, arachidonic acid in particular, and
that might be what is happening here.  The researchers aren't familiar
enough with the literature to even know this much.  My point is, and
has been for years now, that both omega 3s and 6s are too dangerous to
eat except in trace amounts.  I've seen the studies of actual
experiments that documented this (and I've cited them here in the
past).  Your body makes it's own polyunsaturated fatty acid, to be used
for growth and stress (two sides of the same coin), called the Mead
acid, and the evidence suggests that this is best (as does common
sense), but until the experiments are done, we won't know for sure.
I'd be content if rersearches fed dogs, or some other animal that
metabolized fatty acids in the same way that people do, either fresh
coconut oil or a mixture of corn and fish oil, and then determine which
group of dogs live longer.  I've challenged people here to put their
own money, as I would do, and whoever "loses" would then pay for the
entire experiment.  So far, no one has shown any interest.  Not even
one counter-proposal, for example.

":-) That is not very likely as DHA is the most abundant fat in the brain."

But, are we sure about montygram's brain :-o